Ceramic matrix composite (CMC) structures may be used in aerospace and other applications because of their ability to withstand relatively high operating temperatures. For example, CMC structures may be used to fabricate parts subjected to high temperature exhaust gases in aircraft applications. One type of CMC structure employs a sandwich construction in which two CMC facesheets are bonded to a core. In one sandwich construction, the core may be reinforced by a truss-like array of CMC pins which extend through the thickness of the core and penetrate the facesheets. These pins provide load paths along which compressive, tensile and/or shear loads are transferred between the facesheets. The load carrying ability of this prior pin truss construction is limited however, due to the limited bond strength between the ends of the pins and the plies of the facesheets, especially where the facesheets are relatively thin.
The bond strength between the CMC pins and the facesheets may be increased if the ends of the pins could be bent so as to extend parallel to the facesheets, providing a greater bond area. This solution has not been feasible however, because the CMC pins are relatively brittle and may break if attempts are made to bend the ends of the CMC pins.
Accordingly there is a need for a CMC structure having a ceramic truss core exhibiting improved bonding properties between the core and the facesheets. Embodiments of the disclosure are intended to satisfy this need.